Well, to be fair, it's like saying, "I just got a new Mustang, where should I drive?" Well, where do you want to go? It's hard to answer an open ended question without it being :icon_ banana:. There's tons to do with the phone, but there's no one thing to suggest more than any other.

I may be wrong, bet the most common two reasons I hear for people rooting their phones are to use custom ROMs for speed/customization/theming or WiFi tethering. Well, you've got a good custom ROM and the speed. If you want to change the look, search for themes. I'm guessing you didn't need WiFi tethering, so can't think of what else to suggest, other than the naked burrito suggested above.